1. Field of the Invention
The present invention is directed to a technique of a liquid crystal display, and more particularly to a thin film transistor liquid crystal display having an improved hue and a simple process thereof and a method for manufacturing the same.
2. Description of the Related Art
In general, a thin film transistor liquid crystal display includes a lower substrate, a thin film transistor, as a switching device, formed on the lower substrate, an upper substrate opposite to the lower substrate, a color filter of red, green and blue formed on the upper substrate and a liquid crystal sealed within a cavity defined by both substrates.
FIG. 1 is a view showing a cross sectional view of the conventional thin film transistor liquid crystal display(TFT LCD).
On a portion of a lower substrate 1 an etch stopper inverse staggered type thin film transistor 15 (E/S inverse staggered TFT) and on the other portion of the lower substrate 1 a pixel electrode 8 is disposed. The pixel electrode is of ITO. A passivation layer 9 for protecting the E/S inverse staggered TFT 15 is arranged on the E/S inverse staggered TFT 15. The TFT 15 has a gate 2a, a source 7a and a drain 7b. A storage electrode 2b on the same plane as the gate 2a, the pixel electrode 8 and a insulating layer 3 interposed between the storage electrode 2b and the pixel electrode 8, form a capacitor 17. On a portion of the upper substrate 11 is disposed a black matrix 12 for preventing a cross talk of the liquid crystal display. The black matrix 12 is formed on a portion of the upper substrate corresponding to the TFT 15 and the capacitor 17. On another portion of the upper substrate which corresponds to the pixel electrode, the color filter layer 13 of red, green and blue is disposed. A common electrode 14 is arranged on the black matrix 12 and the color filter 13. The common electrode 14 is of ITO. A numeral 4 indicates an active region, a numeral 5 indicates an etch stopper and a numeral 6 indicates an ohmic resistance contact layer.
In order to manufacture such TFT LCD, in one production line, the TFT 15 is formed on the portion of the lower substrate 1. During the formation of the TFT 15 before forming the source 7a and the drain 7b, the pixel electrode 8 is formed on the other portion of the lower substrate 1. Thereafter, the passivation layer 9, for protecting the TFT 15 is formed thereon. On the other hand, in another production line, the black matrix 12 is formed on a portion of the upper substrate 11 corresponding to the TFT 15 and the capacitor 17. The color filter layer 13 is formed on another portion of the upper substrate 11 corresponding to the pixel electrode 8. Then the common electrode 14 is formed over the resultant in which the black matrix 12 and the color filter 13 are provided.
According to the above described manufacturing method, a process for the passivation layer 9 is independently carried out from a process for the color filter layer 13. Accordingly, the process for the LCD is considered complicate.
In addition, two production lies are required so as to make the TFT LCD; one line for formation of both the TFT 15 and the passivation layer 9 on the lower substrate 1 and the other line for formation of the color filter layer 13 on the upper substrate 11. An investment cost on a setting-up of additional production line is much high.